to In applicant""s co-pending application Ser. No. 09/385,532 entitled UNIFORMLY WEIGHTED GOLF BALL, the problem of the core of the golf ball having a different density than the cover of the golf ball is discussed and the erratic behavior of golf balls that do not have the core properly centered when the density of the core and cover is different is set forth. The invention set forth in that application involves making the density of the core and the density of the one or more layers surrounding the core essentially identical. In producing such a ball, there are difficulties encountered in adding heavy additives to the cover in order to have its density the same as that of the core.
The raw materials of the covers are generally provided by the manufacturer in pelletized form. The pellets are then blended with other additives and extruded into the ball molds. Because of the adhesive nature of the cover blends at higher temperature, the blends are heated and melted only just before injection into the mold. This prevents perfect and homogeneous blending of the cover materials with additive particles larger than 0.05 microns since bonding to the pellets is very weak if at all and separation can occur during feeding into the mold.
The present invention provides a method to perfectly blend cover materials and preclude separation during the feeding and heating phases of injection molding of golf ball covers. Prior methods have utilized discreet particles with sizes ranging from approximately 0.5-100 microns in size. These particles do not cling or adhere to the pellets and thus, blending the very large pellets with discreet particles larger than 1 micron is nearly impossible. Applicant""s invention utilizes nano-particles which are approximately 0.05 or less in diameter. Because of their very small size, these small particles cling to the pellets and thus, uniformly cover the entire pellet. The particles do not separate during the heating and extrusion processes and thus provide for a very uniform distribution of the nano-particles in the blended cover material.
It is therefore, a object of this invention to provide a method of making a golf ball cover which comprises adding to the cover materials which are in pelletized form nano particles of denser materials of approximately 0.05 micron or less in size.
It is a further object of this invention to provide a golf ball comprising a spherical core and one or more layers of materials wherein the materials have had nano particles of 0.05 micron or less in size added thereto and wherein the density of the core and the one or more layers of materials are essentially the same. These together with other objects of the invention will become apparent from the following drawings and detailed description of the invention.